Excitations below the Kohn mode; FIR-absorption in quantum dots

Vidar Gudmundsson; Roman Krahne; Christian Heyn; Detlef Heitmann

Excitations below the Kohn mode; FIR-absorption in quantum dots

Vidar Gudmundsson^*, Roman Krahne, Christian Heyn, Detlef Heitmann

^*Corresponding author for this work

Faculty of Physical Sciences

Research output: Contribution to journal › Conference article › peer-review

1 Citation (Scopus)

Abstract

We have investigated the far-infrared (FIR) responses of an array of quantum dots in modulation doped GaAs heterostructures in an external magnetic field. In accordance with the extended Kohn theorem FIR-radiation can only excite the center-of-mass modes of harmonically confined electrons in a dot. In a perpendicular magnetic field the single absorption peak corresponding to the Kohn mode splits in two peaks separated by the cyclotron frequency. We observe novel modes at frequencies below the higher frequency Kohn mode. Comparison with Hartree-RPA calculations show that these modes arise from the flattened confining potential in our field-effect quantum dots. They reflect t pronounced relative motion of the charge density with respect to its center-of-mass.

Original language	English
Pages (from-to)	136-139
Number of pages	4
Journal	Physica Scripta T
Volume	101
Publication status	Published - 2002
Event	Proceedings of the 19th Nordic Semiconductor Meeting - Lyngby, Denmark Duration: 20 May 2001 → 23 May 2001

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title = "Excitations below the Kohn mode; FIR-absorption in quantum dots",

abstract = "We have investigated the far-infrared (FIR) responses of an array of quantum dots in modulation doped GaAs heterostructures in an external magnetic field. In accordance with the extended Kohn theorem FIR-radiation can only excite the center-of-mass modes of harmonically confined electrons in a dot. In a perpendicular magnetic field the single absorption peak corresponding to the Kohn mode splits in two peaks separated by the cyclotron frequency. We observe novel modes at frequencies below the higher frequency Kohn mode. Comparison with Hartree-RPA calculations show that these modes arise from the flattened confining potential in our field-effect quantum dots. They reflect t pronounced relative motion of the charge density with respect to its center-of-mass.",

author = "Vidar Gudmundsson and Roman Krahne and Christian Heyn and Detlef Heitmann",

year = "2002",

language = "English",

volume = "101",

pages = "136--139",

journal = "Physica Scripta T",

issn = "0281-1847",

publisher = "IOP Publishing Ltd.",

note = "Proceedings of the 19th Nordic Semiconductor Meeting ; Conference date: 20-05-2001 Through 23-05-2001",

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TY - JOUR

T1 - Excitations below the Kohn mode; FIR-absorption in quantum dots

AU - Gudmundsson, Vidar

AU - Krahne, Roman

AU - Heyn, Christian

AU - Heitmann, Detlef

PY - 2002

Y1 - 2002

N2 - We have investigated the far-infrared (FIR) responses of an array of quantum dots in modulation doped GaAs heterostructures in an external magnetic field. In accordance with the extended Kohn theorem FIR-radiation can only excite the center-of-mass modes of harmonically confined electrons in a dot. In a perpendicular magnetic field the single absorption peak corresponding to the Kohn mode splits in two peaks separated by the cyclotron frequency. We observe novel modes at frequencies below the higher frequency Kohn mode. Comparison with Hartree-RPA calculations show that these modes arise from the flattened confining potential in our field-effect quantum dots. They reflect t pronounced relative motion of the charge density with respect to its center-of-mass.

AB - We have investigated the far-infrared (FIR) responses of an array of quantum dots in modulation doped GaAs heterostructures in an external magnetic field. In accordance with the extended Kohn theorem FIR-radiation can only excite the center-of-mass modes of harmonically confined electrons in a dot. In a perpendicular magnetic field the single absorption peak corresponding to the Kohn mode splits in two peaks separated by the cyclotron frequency. We observe novel modes at frequencies below the higher frequency Kohn mode. Comparison with Hartree-RPA calculations show that these modes arise from the flattened confining potential in our field-effect quantum dots. They reflect t pronounced relative motion of the charge density with respect to its center-of-mass.

UR - http://www.scopus.com/inward/record.url?scp=0036437385&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:0036437385

SN - 0281-1847

VL - 101

SP - 136

EP - 139

JO - Physica Scripta T

JF - Physica Scripta T

T2 - Proceedings of the 19th Nordic Semiconductor Meeting

Y2 - 20 May 2001 through 23 May 2001

ER -

Excitations below the Kohn mode; FIR-absorption in quantum dots

Abstract

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